As the human population increases worldwide and available farmland continues to be destroyed or otherwise compromised, the need for more effective and sustainable agriculture systems is becoming of paramount interest to the human race. Improving biomass production, crop yields, protein content, plant growth rates, etc. represent major objectives in the development of agriculture systems that can more effectively respond to environmental and economic challenges.
Nitrogen is considered a critical growth-limiting element in plant growth and production. It is a key component of chlorophyll and amino acids and is found in adenosine triphosphate (ATP) and nucleic acids. Plants acquire nitrogen from the atmosphere in the form of N2 gas and/or from the soil (e.g., fertilizer and decomposition of organic matter) but can only use the element in a reduced form (e.g., NH3). The conversion of atmospheric nitrogen (N2) to ammonia (NH3) is “nitrogen fixation” and is carried out via the enzyme “nitrogenase” by a specialized group of prokaryotes that have a symbiotic relationship with the plant. Plants can readily assimilate NH3 and use the molecule as the basis for producing key biological components (e.g., chlorophyll and amino acids) that promote growth and production in the plant.
Unfortunately, nitrogen fixation is a limiting step for plants to acquire NH3, and as a result, modern day agriculture has supplemented with industrially-produced nitrogen fertilizers. That widespread fertilizer use has led to worldwide ecological problems such as the formation of coastal dead zones (due primarily to run-off into streams and oceans), which have a dramatic impact to the marine wildlife.
As a result, there continues to be a need for improved, cost-effective, and ecologically sound compositions and methods to improve plant growth, biomass production, grain yield, etc.